1. Field of the Invention
The present invention relates to an appearance inspection apparatus for detecting minute foreign matters or defects on a semiconductor wafer.
2. Description of the Related Art
There is a technique in which in an appearance inspection apparatus for inspecting a defect on a surface of a wafer, COP (Crystal Originated Particles) defects are discriminated using a scattered light detecting section (which will appropriately be described as a multi-sensor, hereinafter) having a plurality of detectors disposed around an illumination light spot on a sample such that orientations and elevation angles thereof are different from each other, and utilizing a difference in detection characteristics caused by a difference of an elevation angle of the detectors (see Japanese Patent Application Laid-open No. 9-304289 and the like).